A lot of people are wondering why Nokia didn't choose to go with Android. How can Nokia differentiate themselves when Android is a lot more open and free than Windows Phone 7? As usual, the key to this is in the details. If you read the announcements carefully, you'll see that Microsoft offered Nokia something Google most likely didn't. Update: What a surprise. Elop just confirmed Nokia has a special deal with Microsoft. Whereas HTC, Samsung, and so on are not allowed to customise WP7 - Nokia is, further confirming my theory.

Thom, it is not like good .net developers are instantly available and will have great customizations ready in no time. Maybe you should learn a few things about software development. There won't be any deep customizations of WindowsP7 from Nokia anytime soon.
Hiring and integrating people takes time. Especially when you have fire hundreds(thousands) of C++ devs.

And anyways, it is not like a Nokia WP7 phone will be ready tomorrow. It will be the end of the year. A Meego phone could have been ready by that time.